definition: intertwined / twisted / tangled / confused To undo or loosen (a knot or something tied up). 解开 解开 或 松开 （一 个 绳结 或 纠结 在一起 的 某物 ） Confusion or complexity; a tangle. 纠缠 纠结 不清 ；复杂 ；混乱 ；团 在一起 的 东西 To entangle or catch (a rope, for example) 纠结 使 缠 住 或 绊住 （如 绳子 ）

纠结= Entangled ,to twist together or entwine into a confusing mass,to complicate; confuse.

Considering the latest meaning of this "纠结" has changed from its original gist in practical use, I would prefer "dwell on" for its cloest translation. For instance: Do not dwell on those you can't change, just accept and make peace with them; I'm still dwelling on if I should go and confess to her about what I feel for her.